Dear members,
I hope you can provide me a solution to my question. We are using XML to support
client conversation with EJB (via IIOP). The client would pass an XML string
containing the class name and method invocation parameters. A singleton Session Bean
(Factory bean) will parse the XML string and extract the class name and invocation
parameters and call the appropriate EJBean(the EJBean does whatever and returns the
result back to the Factory Bean as an XML string which then passes to the client).
There are many EJBeans register in the same container. My question is how to invoke
the appropriate EJBean dynamically. An example will explain what I mean:
Client will pass the following XML to the Factory Bean:
<QUERY>
<APPHOME>Jndi_CheckingAcct</APPHOME>
<USERINPUT>
<account_id>1002</account_id>
</USERINPUT>
</QUERY>
The Factory bean will parse the XML string to get the Home interface and would like to
do the following (somewhat achieving polymorphism):
String home_str = Parser().getHomeStr;
// home_str = "Jndi_CheckingAcct"
BaseAccount acctHome = jndiContext.lookup(home_str);
String acct_id = Parser().getAcctId;
// invoke the appropriate bean, in this case the
// CheckingAcct bean
acctHome.create(acct_id);
We don't want to have to do this:
if (home_str == "Jndi_CheckingAcct") {
CheckingAcct acctHome =
(CheckingAcct)jndiContext.lookup(home_str);
acctHome.create(acct_id);
}
if (home_str == "Jndi_SavingAcct") {
SavingAcct acctHome =
(SavingAcct)jndiContext.lookup(home_str);
acctHome.create(acct_id);
}
if (...) // you get the idea
Using XML between client/server shields us from interface changes in the future. So
later if we decide to add dirrerent account beans later we don't have to change the
interface. The client can't call the CheckingAcctHome to get the reference directly
because everthing is funnel through the Factory bean (thus, using XML).
I know the CORBA services provide the interface repository where you can do dynamic
lookup and construction of a server object and its methods. I'm looking for something
similar in EJB. How do I achieve this?
Please comment.
Thanks in advance,
Thong Le
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